It seems to strike when we least expect it.

NHRA Funny Car driver John Force once called it “The Monster” — that dark side of racing, of danger and sometimes death, which lurks in the shadows of every corner of every racetrack.

And last weekend, it got Dan Wheldon.

Just five months ago, Wheldon was on top of the world, basking in the emotional glory of a dramatically unexpected Indianapolis 500 victory.

On Sunday at the IZOD IndyCar World Championships in Las Vegas, Wheldon had another shot at winning, along with a $5 million-dollar bonus if he did so, in the series’ final event of the 2011 season.

But on the race’s 11th lap, all that changed in a fiery crash that gobbled up 15 cars. Wheldon couldn’t avoid the accident, sailing over the top of another car, his No. 77 Dallara chassis flipping wildly and striking the catch fence cockpit-first.

As drivers got out of their wrecked machines, and as safety crews tended to them, it was clear something was wrong. Too much attention around Wheldon’s car, but no even moderately-tight camera shots. During the helicopter ride to the hospital no word was given on Wheldon’s condition. A yellow tarp draped over the car.

It all just seemed like posturing for the tragic news that was to come two hours later.

I’ve been a race fan for more than ten years now, and in that short time, I’ve watched a lot of wrecks — some more terrifying than others, some of them fatal. Last year, I was unfortunate enough to be at the NHRA Northwest Nationals in Seattle when Top Alcohol Dragster driver Mark Niver was killed.

And so, from time to time, you think about the risk of death that participants and fans subject themselves to while at the racetrack. But when the knowing hypothetical becomes a crushing reality, you still never seem to be prepared.

Safety was a concern heading into Sunday’s race, but was somewhat overshadowed by the hoopla of a championship being decided and a potential big money bonus.

Practice speeds of up to 224 mph were recorded by pole sitter Tony Kanaan, and there was a record 34-car field. The Las Vegas track, with its relatively tight corners, led to concerns about pack-racing, where the cars drive clustered together just inches from each other and potential disaster.

There is something alluring, perhaps almost perversely so, of subjecting people to great danger in the name of entertainment.

But we do it because it is exciting to see these men and women, high-horsepower gladiators, putting their lives on the line for a shot at fame and fortune while negotiating the paper-thin edge of control.

The drivers, most of all, know and assume the risk. They do it because they love it, and because in their mind, reward usually outweighs that risk.

But Sunday, as drivers hugged their families and crews before taking part in a rolling five-lap tribute to Wheldon while a bagpipe version of “Amazing Grace” played over the track PA, it was sadly clear the risk was more.

Wheldon, a two-time Indy 500 winner and former IndyCar champion, was just 33. He left behind a wife and two children and a family that includes a mother with Alzheimer’s disease.

In this modern age of professional auto racing, where so many safety advancements allow drivers to commonly walk away from horrible wrecks, it can be easy to forget how dangerous the sport really is. The human body cannot evolve along with technology.

With another life lost amid the carnage of flame and flying sheet metal, how high a cost it is to be reminded.